Rotational grid, PAI maximizing Crime Forecasts George Mohler Indiana University – Purdue University Indianapolis PredPol Mike Porter University of Virginia PASDA BRIEFLY INTRODUCE YOURSELF AND YOUR INVESTIGATORS (10 sec slide)

NIJ Solution CrimeRank Policing Fairness Social Harm Crime Models Should Address long-term intrinsic risk short-term dynamic risk time of day/day of week trends (not applicable for NIJ Challenge)

NIJ Solution CrimeRank Policing Fairness Social Harm Crime Models Should Address long-term intrinsic risk short-term dynamic risk time of day/day of week trends (not applicable for NIJ Challenge) geometry of city evaluation metric (PAI or PEI)

NIJ Solution CrimeRank Policing Fairness Social Harm Our approach parameterize grid cell features point processes counts supervised learning random forest sparse regression simplex method to maximize PAI Mohler and Porter, Rotational Grid PAI Maximizing Crime Forecasts, Statistical Analysis and Data mining, 2018.

NIJ Solution CrimeRank Policing Fairness Social Harm Our approach parameterize grid cell features point processes counts supervised learning random forest sparse regression simplex method to maximize PAI Mohler and Porter, Rotational Grid PAI Maximizing Crime Forecasts, Statistical Analysis and Data mining, 2018.

NIJ Solution CrimeRank Policing Fairness Social Harm Our approach parameterize grid cell features point processes counts supervised learning random forest sparse regression simplex method to maximize PAI PAI COMPETITION TABLE Mohler and Porter, Rotational Grid PAI Maximizing Crime Forecasts, Statistical Analysis and Data mining, 2018.

NIJ Solution CrimeRank Policing Fairness Social Harm Mohler & Porter et al, Learning to Rank Spatio-Temporal Event Hotspots, UrbComp 2018.

NIJ Solution CrimeRank Policing Fairness Social Harm Model the “gradient” of PAI Fit a regression tree to the gradient Update score Si with one step of gradient ascent Mohler & Porter et al, Learning to Rank Spatio-Temporal Event Hotspots, UrbComp 2018.

NIJ Solution CrimeRank Policing Fairness Social Harm Mohler, G. O., Short, M. B., Malinowski, S., Johnson, M., Tita, G. E., Bertozzi, A. L., & Brantingham, P. J. (2015). Randomized controlled field trials of predictive policing. Journal of the American Statistical Association, 110(512), 1399-1411. 7% reduction in crime, 30 min patrol a day Ratcliffe, Jerry H., et al. "The Philadelphia foot patrol experiment: A randomized controlled trial of police patrol effectiveness in violent crime hotspots." Criminology 49.3 (2011): 795-831. 23% reduction in crime, 16 hours of foot patrol a day Saunders, Jessica, Priscillia Hunt, and John S. Hollywood. "Predictions put into practice: a quasi-experimental evaluation of Chicago’s predictive policing pilot." Journal of Experimental Criminology 12.3 (2016): 347-371. no difference between treatment and control

NIJ Solution CrimeRank Policing Fairness Social Harm

NIJ Solution CrimeRank Policing Fairness Social Harm Lum, Kristian, and William Isaac. "To predict and serve?." Significance 2016. Brantingham, P. Jeffrey, Matthew Valasik, and George O. Mohler. "Does Predictive Policing Lead to Biased Arrests? Results From a Randomized Controlled Trial." Statistics and Public Policy  2018. G. Mohler, M. Porter, R. Raje, J. Carter,  M Valasik, and PJ Brantingham.  A penalized likelihood method for balancing accuracy and fairness in predictive policing.  SMC2018. biased feedback loops possible: drug crime bias not detected in property crime field trial demographic parity through MPLE, at cost to PAI

NIJ Solution CrimeRank Policing Fairness Social Harm Ratcliffe (2015) “Towards an Index for Harm-focused Policing” Policing 2015. Sherman et al (2016) “The Cambridge Crime Harm Index: Measuring Total Harm from Crime Based on Sentencing Guidelines” Policing 2016. Mohler, Carter, and Raje (2018) “Improving social harm indices with a modulated Hawkes process” International Journal of Forecasting 2018. Why not take a cost-benefit analysis point of view. There wasn’t anything necessarily special about burglary and vehicle crime in our trial. Several criminologists have proposed social harm indices to be more systematic in the approach to policing. Here the cost of crime is quantified, which could be monetary, prison sentence length, or an integer score. Indianapolis: 12.5% of $1billion/yr captured in 1% of city

Acknowledgements National Institute of Justice National Science Foundation Smart and Connected Communities Algorithms for Threat Detection Andrea Bertozzi (UCLA Math) Jeff Brantingham (UCLA Anthropology) George Tita (UC Irvine Crim) Martin Short (Georgia Tech Math) Matthew Valasik (LSU Crim) Jeremy Carter (IUPUI Crim Justice) Rajeev Raje (IUPUI CS)